This should be an adult male, based on the palps. My first impression was Zygiella but as I am by no means an expert I cannot confirm that at all and I was just wondering if the quoted size of 10 mm then perhaps is not a but too much for a male of that genus.

Ah ha - now we can see that it is a male Zygiella, the Missing Sector Orb Weaver - prob. Zygiella x-notata. Males of this species are venturing inside my home at the moment the females they are looking for can be found in the corners (outside) of almost every window on the house.